Here are several rules from last Thurs game.
JJ typing, Ghosthelm Eldar Codex 6th ed pg 66
If a model with a ghosthelm suffers an unsaved Wound from Perils of the Warp, he can prevent it by immediately expending a Warp Charge point (if he has one).
Context: Eldrad casted Eldritch Storm and rolled two 6's. Opponent thought Ghosthelm was a one use item. Looked it up to confirm. It is not.
Staff of Ulthamar - Spiritlink Eldar Codex 6th ed pg 53
Whenever Eldrad passes a Psychic test, roll a D6. On a score of 5 or 6, Eldrad immediately regains a Warp Charge point.
Context: Opponent failed a psychic test and wanted to use staff to regain a warp charge. Looked that up, you can only regain a warp charge on a successful test not failed.
Barrage, second bullet point 40k6 pg 34
To determine whether a unit wounded by a Barrage weapon is allowed a cover save, and when determine Wound Allocation, always assume the shot is coming from the centre of the blast marker, instead of from the firing model.
Context: Shawn was punishing my poor Purifiers with Vaul's Wrath Support Battery armed with Shadow Weavers. Guess I was grasping for straws with Aegis Defense Line cover save. Shawn reminded me cover saves count from centre of barrage blast maker not firer.